US2726027A - System and apparatus for filling and closing cans containing pressure propellant andother ingredients - Google Patents

Description

Dec. 6, 1955 H. D. NORTH, JR., ET Al.

SYSTEM AND APPARATUS RoR FILLING AND CLOSING CANS coNTAINING PRESSURE PRORELLANT AND OTHER INGREDIENTS 2 Sheets-Sheet l Filed May 9. 1952 Dec. 6, 19:15 H. D. NORTH, JR., ET AL 2,726,027

SYSTEM AND APPARATUS FOR FILLING AND CLOSING cANs OONTAINING PRESSURE PROPELLANT AND OTHER INGREDIENTS Filed May 9, 1952 2 Sheets-Sheet 2 H www.

STA RT United States Patent Ofiice 2,726,027 Patented Dec. 6, 1955 SYSTEM AND APPARATUS FOR FILLING AND CLOSING CANS CONTAINING PRESSURE PRO- PELLANT AND OTHER INGREDIENTS Harold D. North, Jr., Shaker Heights, and Robert J. Stetz,

Westlake, Ohio, assignors to The Engine Parts Manufactoring Company, Cleveland, Ohio, a corporation of Ohio Application May 9, 1952, Serial No. 286,856

1 Claim. (Cl. 226-70) This invention relates to a process and apparatus for mixing liquified gas with an active ingredient in an aerosol can, including filling, capping, testing and preparing the can for shipment and use.

In the course of filling an aerosol can with a mixed active ingredient and a liquiiied gas, it is essential that the active ingredient or element, which may be paint,`

insecticide, varnish, or the like, be at a low temperature consistent with that necessary to mix with the gas material which may be liquified dichlorodifuoromethane or trichlorodiuoromethane, or the like (Freon).

Such a liquified gas must be maintained at a low temperature to prevent evaporation. The evaporation must be minimized until after the capping and closing of the can. Following the comingling of the material and the gas, and the closing, it is essential to test the cans for leakage under cold or low temperature condition, followed by a required test at a higher temperature, substantially above that of normal room temperature. T o this end the closed and capped cans are immersed for predetermined period in cold liquid (water) and then are immersed in hot water for further test under the resulting higher pressure of the ,contained propellant.

The filled and tested cans are then given incidental detail treatment'and inspection, and may be labeled and packed for shipping.

Heretofore, the bringing together of the materials at the proper temperature in the can has afforded both mechanical difficulties and time-consuming preparatory steps. t

.p The filling is simplified by the present method, and it has been found that by carrying out the process with a simple apparatus illustrated andhereinafter described, that with different types of active ingredients or material in the can, the balance of the can may be filled with the liquiiied'gas, and the subsequent steps carried out without the delays heretofore encountered in the preparatory and filling steps.v For example, canstcontaining the material to be mixed with liquified gas have been subjected to low temperature in apparatus such as a special deep freeze device which requires opening and closing the chamber, and if progressive or continuous movement is attempted it becomes necessary to automatically open and close the entrance and exit.

Furthermore, the step of -subjecting the can in partially filled condition, that is, with its active ingredient content, to very low air temperature, involves difficulty in attaining precise control and is not effective in utilization of the low temperature-producing means.

In carrying out the present invention, the cans are partially filled at room temperature with the desired active ingredient to the precise predetermined amount, as by scale-controlled filling apparatus. These partially filled cans are then placed in a carrier or basket with others, and the cans, with the tops open, are partially immersed in.an elongated shallow Vbody of brine in an open tank. While cooling the cans may be progressed, over a period of time, from one end of the brine tank to the other.

When the cans and the active ingredient are chilled yto the desired temperature of approximately zero Fahrenheit, they are then removed from the open tank. The open end of the can is then placed under a spout supplying liquified gas fed through a cooling body and insulated pipes. The pipe or conduit for the liquified gas may be passed in a series of turns through the same body of cold brine in the tanknboth for convenience and simplicity and cheapness of construction. By so doing one refrigerating apparatus only is needed to maintain the desired low temperature of the brine, which cools both the active ingredient and the liquified gas. The filling of the cans to a desired amount may also be controlled by a scale-operated valve, and the can and its contents in this cold'condition are moved to a capping device which seals the cover end on the can. A suitable valve on the cover is now closed, sealing the contents therein. While still cold the cans are arranged for easy inspection for the detection of any leaks. They are then completely immersed in another open shallow tank containing cool to warm water. Next, they are immersed in hot water of a temperature required by safety regulations, the temperature varying according to the nature of the can and to the pressure generated by the liquified gas and other conditions.

The water in this open tank may be maintained, for example, at 140 F. for an aerosol can which normally expels its contents under 35 or 40 pounds per square inch of internal pressure at normal room temperatures. Thus, for example, if the liquified gas is Freon, dichlorodiuoromethane and trichlorodiuoromethane, that temperature will result in a test of internal pressure at to 80 pounds.

The liquid in the brine tank should not be allowed to spill into the cans. To assure cooling the contents, the brine level should come to a point near the top of the can, say, an inch or so from the top, when the cans are held in baskets resting on the supports in the brine tank. These baskets may be moved along progressively, the desired cool temperature being assured by the time the cans reach the end opposite from that at which they were putin, and from where they are removed for completing the filling with a liquified gas.

In the accompanying drawings is illustrated a diagrammatic arrangement of apparatus and the order of the movement orflow sequence of the cans, and also accom-l y panying diagrammatic illustrations of the scale-control can-filling devices, etc.

Referring to the drawings:

Fig. 1 is a diagram of the apparatus used in carrying out our process, and in which the rectangles and legends associated therewith indicate the steps and order of sequence;

Fig. 2 is a somewhat diagrammatic view showing the scale filling brine tank capping and testing apparatus in side elevation, andV continuing with the finishing steps indicated by rectangles and legends;

Fig. 3 is an elevation of the can top and valve body about to be placed on the can; and

Fig. 4 is an elevation of the upper portion of the can with the top, valve body and valve in position.

As indicated in the diagram in Fig. 1, the active ingredients and containers are brought together at the filling scale position indicated by the rectangle and as indicated by the legends.

Referring to Fig. 2 by the use of reference characters, this first step constitutes partially filling a can C supported on a scale platform 10, indicated diagrammatically as bal- I anced on the pivot 11 and as having an adjustable weight 12 on the side of the pivot opposite that of the canlsupporting platform. y

When suiicient weight of the ingredient in thel can t C causes the scale to tip, an electric switch, indicatedgff at 15, is closed, which, in turn, through wires indicated at 16, operates van eleetromagnet 17 to close `a valve, indicated at 18, cutting off the ow of the ingredient through the pipe 20 to the filling spout 22, shown as adapted to discharge into the top of the can C.

Thus, whatever amount is desired may be regulated by adjusting the scale to cause it to tip and close the valve when the can is partially filled to a given predetermined weight.

Obviously, this operation may be very quick, and as soon as the can C is removed, another may be placed in position to receive flow of the ingredient from the nozzle 22, which again continues to ow until the switch 15 `is again closed to close the valve 18.

The cans thus partially filled tothe desired amount may be set into a suitable shallow basket-like container at an adjacent position as on a platform 26 at the end of 4a shallow tank 30. The filled baskets 25 containing say, a dozen or vmore cans, may be set into a cooling liquid, such as a brine Vindicated at B in the shallow tank, while a suitable supporting screen 32 holds the basket and cans with the open can tops above the surface of the cooling liquid.

The cans Vin their baskets may be moved along from left to right in Fig. 2, and thence upwardly to a support 35 from which the partially filled cans may be placed on the platform of another scale, shown as having a pivot 41 and a weight 42, and arranged to actuate a switch 45 in a circuit, indicated at 46, controlling a solenoid 47, in `turn acting to close a valve 48.

A pipe line for liquified gas is shown as discharging through the nozzle 52 into the can C on the scale sothat the weight of the added liquilied gas when tipping the scale may effect a shutting off of the flow of the liquifed gas to the can.

Referring to Fig. l as well as to Fig. 2, it will be noted that the rectangle 30 `indicates the shallow brine tank just described, and the line 50a diagrammatically illustrates a pipe leading through the cooling liquid in the tank 30, preferably below the supporting screen, and to the valve 48 and nozzle 52. Thus, the propellant, i. e., the liquitied gas, is brought to the can C at about the same temperature as the contents of the can, that is, the ractive ingredient, which has been chilled to a temperature below the freezing point of water, preferably in the approximate range of a few degrees below to a few `degrees above zero Fahrenheit.

The rectangles designated Refrigerating equipment" are shown as connected with cooling coils inthe liquid within the shallow tank 30 to hold the temperature of the brine at the desired low temperature.

It has been found that even though lthis shallow tank is left open, the eiliciency is not measurably reduced and the accessibility, permitting easily moving the can-holding baskets along inthe cooling liquid, makes for great convenience in carrying out the steps of Vthis process.V

The rectangle marked Capping corresponds to the platform #in Fig. 2, above which are two rotating spindles and 75. The spindles 70 acting to crimp the :Bange of a can top closure D into sealing engagement with the top of the-can, while the lspindle may serye to spin the screw valve V into position, Vsealing the can closed.

The Yrectangles carrying the legends Cold leak test and Hot tleak test correspond to the one `having cold water, as Yindicated at W, and the other having Warm water, as indicated at WW.

The closed cans which are, of course, -still cold are passed in a matter of seconds from the valve-closing position to the cold or room temperature water W Where the cans are immersed, as indicated, and are there obser-ved for leakage which would show by bubbles rising to the surface. Here they may remain for any suitable period `sufficient for the temperature of the contents t0 approach room temperature. These cans are then transferred to the container .of warm water WW which may be at a temperature of to 150 F., or more if desired, the temperature depending upon the nature of the propellant, the amount of it, and the degree of internal pressure for which it is desired to test the cans.

After a sutiicient interval in the warm water, the cans are then removed and passed along `to aseries of stations, indicated in both Figs. l and 2 as Incidental and detail inspection, Labeling and packing, and Shipping and packaging.

While the nature of the can top closure may vary, a type extensively used is that shown in Fig. 3, in which a flange 8i) embraces a flange 82 on the top of the can C, and is crimped and spun into position by a suitable die in the pressure member 70, which, as indicated, may be a rotating spindle or may simply seal the cans by pressurecrimping, if desired.

The valve comprises a suitable screw stem S in Fig. 4 which is threaded into the lvalve body V84 `previously assembled with the can covered element having a flange Sil. The valve body is provided with the usual nozzle or nozzle opening, indicated at 85.

Following the steps briefly, it will be seen from the foregoing description that the empty open top cans may be set on the scale platform 10 for only a second or two of time, while the desired amount of paint, insecticide, varnish, or other .active ingredient is discharged therein through the spout 22, `and-that the precise amount desired will `be governed by the scale, the movement of which controls the solenoid operated shutoff valve.

The partially filled cans containing this active ingredient are then transferred to the baskets, or like suitable containers or holders 25, which, as indicated, are open framework or open wire, or the like, to permit circulation of the cooling liquid around the cans.

As they are moved along at intervals on the support 32, they are cooled for a matter of minutes down to a few degrees above `or below zero Fahrenheit.

The liquid propellant in the form of liquified gas is likewise weighed into the .can by discharging the precise amount desired through the spout S2 under the control ofrthe scale and solenoid circuitand valve 48.

The capping device which closes the cover and seals it on the can, as indicated, may be of any suitable formdepending on the can construction.

The capping and inserting and tightening of the valve member is likewise quickly done, and with such control as is suitable to avoid injuring the valve stem or making the valve too tight.

The closed and sealed .cans Inow containing the desired mixture of active ingredient and propellant, and both at alow temperature, are then'first observed while submerged in cool waterbut substantially warmer than the temperature of the contents of the filled can.

As the contents approach room temperature, the cans are again tested and observed while submerged in warm or hot water, which causes the propellant to create a pressure comparable to that required for a safety test.

The tested cans are then inspected, labeled, packed and shipped, as indicated.

The advantages in addition to convenience and simplicity of the apparatus required for carrying out my processare that while using uniform ingredient and `propellant, the handling of the cans and material may coniinue uninterruptedly and at a very economically efficient rate of speed ata minimum of labor and with assurance and precision as to the chilling temperatures and accurate filling.

Furthermore, when changing from one active ingredient to another, such, for example, as from a roach spray to a fly spray ingredient, or when changingfrom one color of paint to another color of paint ingredient, n0 change 'is necessary in the apparatus, and any desired change in the degree of cooling may be controlled very simply by merely lowering or raising the temperature of the brine in the tank. Thus, it is equally simple and elhcient, as well as economical, to run a small batch of a few hundred or a few thousand of one kind of ingredient with an appropriate propellant, or to make continuous runs of a great many thousands.

While the temperature of the liquid propellant is lowered for the lilling by running its feed pipe through the same brine tank, this is a convenience, but obviously is not necessary. Separate chilling or refrigerating means may be used for cooling and propellant.

It is necessary, however, that the ingredient be put into the can in liquid form and to the right amount, and that it then be cooled to the low temperature which is desired for maintaining the liquid condition of the propellant.

Obviously, if the ingredient were substantially warmer than the propellant, it would be impossible to fill the can with the liquid propellant. Much of the propellant would be lost in gas, and the remainder would be enough to create the necessary propelling pressure for later discharging the contents of the can.

The propellant normally used for such active ngredients as mentioned may be a mixture in suitable proportions of liquied dichlorodiliuoromethane and trichlorodiuoromethane.

Having thus described our invention, what we claim is:

A process of filling aerosol cans with an active ingredient and a liquied gas for a propellant adapted to exert superatmospheric pressure at normal temperatures, comprising pouring an active ingredient into the open can and controlling the amount by shutting off flow consequent upon the weight reaching said amount, immersing the major portion of the can with ingredient therein in an open brine tank with the brine liquid level below the open top, cooling the contents and can below freezing temperature of water, removing the can from the brine, and adding cold liquifed gas in amount controlled by its own weight, and then capping and sealing the can with an aerosol valve therein while the contents are still cold.

No references cited.

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